Process for annealing mandrelless coils



April G, 194. F. E;l SUTTER 2,197,533

PROCESS FOR ANNEALING MANDRELLESS COILS Filed Sept. 50, 1937 2Sheets-Sheet 1 ATTORNEY April 16, 1940. 2,197,533

F. E. SUTTER PROCESS FOR NNEALING MANDRELLESS COILS Filed sept. zo,1937.

2 Sheets-Sheet 2 INVENTOR Ff. 607727? BW MMM/mm ATTORN EY Patented Apr.l5, i949 `UNIT-ED STATES APATENT oFFicEj- PROCESS FOB. ANNEALINGMANDRELLESS COILS y of Pennsylvania Application September 30, 1937,Serial No. 166,604" f '7 Claims.

The present invention relates to the method of and apparatus fortreating metals and has particular reference `to annealing mandrellesswound tungsten filaments for incandescent electric lamps.

At the. present time 'it is well known in the art to employ tungstenfilaments for incandescent lamps which are of the mandrelless coiledtype and are formed by automatic machines without the necessity ofutilizing a mandrel. However, inasmuch as the filaments are oi' arefractory metal, such as tungsten or the like, further manufacturingsteps have heretofore been required. For example, it is necessary inorder to insure uniformity in the Wattage of the finished lamp that thefilaments be of a preselected length and turns per inch.

To facilitate manufacture, the filaments must be slightly annealed sothat they can be handled with ease without distortion as would otherwiseresult because of the brittle-,ness of the refractory metal.l-leretofore, processing of the iilament has required various stepsnecessitating separate handling for each operation which naturallyincreased manufacturing losses known as shrinkage due to distortedfilaments.

It is accordingly an object of the present invention to provide 'amethod wherein the filament is completely treated immediately upon itsinitial formation without the necessity oi' handling the filament exceptto secure the same to the leading-in wires constituting a part of themount for incandescent lamps.

Another object of" the present invention is the provision of a methodfor annealing mandrelless wound lfilaments for incandescent lamps whichenables standardizing of the filaments from the standpoint of length andturns per inch and at the same time conditions the filament `forincorporation in an incandescent lamp immediately following its initialformation.

Another object of the present invention is the provision of a heattreating furnace which con-- stitutes substantially an integral part ofan automatic coil winding machine for the purpose of treatingmandrelless wound filaments A.for incandescent lamps immediatelyfollowing their initial formation.

Another object of the present invention is the Y Another object of thepresent invention is the provision of a heat treating furnaceforvlncandescent lamp filaments forming substantially an integral partof a coil winding machine wherein the incandescent lamp filaments areindividually raised to an annealing temperature which sets and cleansthe laments as they are discharged from the machine Still furthervobjects of the presentinvcnti'on will become obvious to those skilledin the 'art by reference to the accompanying drawings where- Fig. l isan elevationalside View ofthe furnace for treating incandescent lamp'filaments ati tached to and forming substantiallyan integral part of amandrelless coil winding machine.'`

Fig. 2 isa side View partly in cross section and on an enlarged scale ofthe furnace as shown in Fig. `1,' and Fig. 3 is an end View partly incross section taken on the line III--III of Fig. 2 and looking inthedirection indicated by the arrows. Referring now to the drawings indetail a coil winding machine` of any suitable type` is partially showngenerally at 5. Since the coil winding machine itself forms no `partlofthepresentinvention, except insofar as thepresentinyention is applicablein combination.tlfierewith,v so as` to form substantially an integralpart lthereofurther description of the coil winding portion of themachine is deemed unnecessary.V Suffice it to say that such machine maybe of any particular type which winds coiled filamentary *sectionswithout the necessity of employing a mandreL' suchfor example,` as themachine shown and described in United States Patent No. 1,670,499,

, issued May 22, 1928, to J. W. EkStedt, and as*- signed to the sameassignee as the present inven tion.` A

` As shown and described in this patent the fcoiled iilamentary sectionsare discharged from the machine after being cut into predeterminedlengths depending upon the'particular wattage desired for the finishedincandescent electric lamp. The present invention pertains moreparticularly to an electric furnace, Vshown generally at 6, and disposedadjacent the point yof discharge of the mandrelless coiled lamentarysectionsv and thus constituting substantially an integral part of theentire` apparatus.

This furnace is supported by a plurality of adjustable brackets 'l whichare secured to an inclined plate the latter ci which iis-in turn'supported by uprights 9, extending from a channelmember l0 andconstituting a base portion of the coil winding machine 5. A transformerl2 is supported by the base portion It `which supplies electrical energyto the furnace t through suitable switches and a controlling resistanceor rheostat,` as designated in Fig. 1.

In addition electrical energy may also be supplied by the transformer l2to an electric motor.

i3 and a vibrator Hl which are utilized for a purpose toy be hereinafterdescribed morein detail.` A receptacle l5 is shown secured to one of thefurnace supports or uprights 9A or'receiving the annealed coiledlamentary sections' follow,- ingA their discharge` from` the coilvwinding ma,-

chine and treatment during passage through th furnace 6. y

As shown more in detail in Fig. 2, the furnace 6 may be of cylindricalform and comprises a tube of suitable material It, such as isolantite orthe like, which acts as an insulator for an electrical heating' elementI'I and at the same time possesses comparatively good thermalconductivity. In

order to heat insulate the exterior of the fur' nace, the heatingelement I'I surrounding the isolantite tube I6, may be coated with asuitable material, such as magnesium -oxide I3. A pair of bushings I9are interposed between the isolantite tube I6 and the adjustablebrackets 'l to retard heat transfer to the inclined plate 8 inasmuch asthe isolantite tube is at a high temperature during operation of -thefurnace.

The heating chamber of the furnace may consistl of' a metallictube 20,such as nichrome or the like which is disposed concentrically withrespect to the isolantite tube I and passes loosely through the bushingsI9. One end of this nichrome tube 20 is suitably journalled in a bracketbearing 22 secured tothe inclined plate 8 so as to dispose the open endof the nichrome tube in juxtaposition with the discharge tube 23 (Fig.1)t of the coil winding machine. Similarly the opposite end of thenichrome tube is journalled in a `block 24A constituting substantially aT-fitting, one 'opening of which discharges into the receptacle I5(Fig. 1) and the opening normal to the intake and discharge openingscommunicating 'with a source of wet hydrogen gas.

. For the purpose of rotating the furnace, inasmuch as the nichrome tubeconstitutes the heating chamber thereof, the nichrome tube 26 has a gear25 secured thereto which is journalled in a suitable roller bearing 26,the latter being supported by a bracket 27, and this gear 25 meshes witha gear 28 constituting one of a setof reduc'- tion gearing connected tothe shaft of the electric motor I3. The roller bearing 26 together withthe-bracket 21 are supported by an L-shaped bracket 29, which in turn isconnected to a re- 'silient support Si! secured to the inclined plate 8,and supporting the vibrator I4. In order to limit the vibration'of the,furnace a buffer 32 of rubber or the like is secured to the inclinedplate 8 inv alignment with the' bearing 26 and bracket 21.

'Ihe operation o'f the device is as follows: the main line switch shownin Fig. l is first closed, followed by closure of the heating switch andadjustment of the rheostat and the furnace brought up to the desiredtemperature of approximately 1100 C. After the furnace has reached thedesired temperature the source of wet hydrogen gas is allowed to flowthrough the fitting 2li and furnace tube 2l), exhausting at the oppositeend cf the furnace in the form of a flame. The `coil winding machine isnext started which thus forms the coiled iilamentary sections and.discharges the same at a predetermined rate and of preselected length,as more fully shown and described in the aforenoted patent.

The vibrator and motor switches having been closed at the time ofstarting of the coil winding machine, the coiled filamentary sectionsdischarge from the machine through the tube 23 and gravitate into thefurnace 6 by passing into the nichrome tube 2E. Since the furnace isinclined vby virtue of being supported by the `inclined plate 8, thecoiled lamentary sectionsv slowly gravitate the entire length of thefurnace at a speed determinable by the angle of the furnace, which isadjustable for this purpose, and

are finally discharged into the receptacle I5.

However, in order to assist gravitation of the coiled filamentarysections, as Well as uniformly heat the sections, the nichrome tube 20is slowly rotated by the motor I3 and gears 25 and 28 in the bearingsformed in the bracket 22 and the T-tting 24. At the same time the tube20 is slightly` vibrated by the vibrator Ill, due to the resilient softrubber support 3E) which supports the vibrator as well as the bracket 29together with the bracket or support 2'I and roller bearing 26.Moreover, the nichrome tube 20 passes loosely through the bushings I9and the gear assembly is loosely supported by the buffer 32 whichpermits slight vibration of the furnace. It should perhaps also be notedthat while the tting I4 is rigid and one end of the tube 20 isjournalled therein, the tube is of sum-cient length to allow for aslight vibration which is enough to assist gravitation to prevent pilingup of the coiled filamentary sections.

Accordingly the mandrelless coiled lamentary sections, immediatelyfollowing their initial formation, are discharged into the furnace 6.During their gradual gravitation they are subjected to a temperature ofapproximately 110Do C. in an atmosphere of wet hydrogen which thusraises each individual section to the temperature of the furnace beforethey are discharged into the receptacle I5. Since the nichrome tube 2li,forming an integral part of the furnace, rotates this permits freeaccess of the wet hydrogen gas to all parts of the coil giving auniformity of heat and cleaning treatment.

By subjecting the coils to a temperature of approximately 1l00 C.simultaneously with an atmosphere of wet hydrogen gas each individualcoiled section is annealed and set which permits of its immediateincorporation on a mount for incandescent lamps without furtherhandling. Moreover, the coiled sections are thoroughly cleaned of theaquedag coating and other impurities accumulated thereon during previousformation.

Also by having the annealing furnace substantially as an integral partof the coil winding machine the operator can readily check the machineto ascertain if the sections are being cut to the proper length andturns per inch as well as their contraction after heat treating thereofwhich determines their resiliency'.

It thus becomes obvious to those skilled in the art that the presentmethod and apparatus enables the complete formation of mandrellesscoiled filaments for incandescent lamps lby annealing the sameimmediately following their initial formation. Furthermore the sectionsare individually cleaned and annealed immediately following theirformation which eliminates the necessity for further handling therebydecreasing possibility of manufacturing losses due to breakage.Moreover, a uniformity of cleaning and heating is obtained inasmuch asthe individual coiled filaments do not shrink or contract as in priortreatments.

Although one embodiment of the present invention has been shown anddescribed, it is to be understood that various other modifications ofthe same may be made without departing from the spirit and scope of thevappended claims.

I claim:

1. An apparatus for forming and treating filaments for incandescentelectric lamps comprising means for winding coiled filaments intosections of predetermined length in the absence rIIS of a mandrel, meansfor discharging said formed lamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising a furnace, means for `gravitatingsaidY coiled sections through said furnace immediately following theirformation, means for heating said sections during their passage throughsaid furnace to definitely set said individual sections, and means forpassing a gaseous atmosphere through said furnace and into contact withall portions of each individual coiled filamentary section to thoroughlyclean the same.

2. An apparatus for forming and treating filaments for incandescentelectric lamps comprising means for winding coiled filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said formed iilamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising a furnace provided with a tubularheating chamber, means for rotating said tubular chamber to uniformlyheat all portions of said coiled iilamentary sections as they gravitatethrough said heating chamber immediately following their initialformation, means surrounding said heating chamber for heating saidcoiled sections to definitely set said individual sections, and meansfor passing a gaseous atmosphere through said heating chamber and intocontact with all portions of each individual coiled section tothoroughly clean the same preparatory to their incorporation inincandescent electric lamps.

3. An apparatus for forming and treating laments for incandescentelectric lamps comprising means for Winding coiled filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said formed filamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising an inclined furnace provided with atubular heating chamber, means for gravitating said coiled filamentarysections through said furnace immediately following their initialformation, means surrounding said heating chamber for uniformly heatingsaid coiled filamentary sections as they pass through said heatingchamber to denitely anneal and set said sections, and means for passinga gaseous atmosphere through said heating chamber for contacting allportions of each coiled fllamentary section to thoroughly clean the samepreparatory to their incorporation in incandescent electric lamps.

4. An apparatus for forming and treating laments for incandescentelectric lamps comprising means for Winding coiled filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said formed illamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising an inclined furnace provided with atubular heating chamber, heating means surrounding said tubular chamberfor supplying heat thereto, means connected to said tubular chamber forcausing rotation thereof to enable said coiled filamentary sections tobe uniformly heated as they gravitate through said heating chamber toanneal and definitely set said sections, and means for passing a gaseousatmosphere of Wet hydrogen through said tubular chamber and into contactwith all portions of each individual section to thoroughly clean thesame preparatory to their incorporation in an incandescent electriclamp.

5. An apparatus for forming and treating filaments for incandescentelectric lamps comprising means for winding coiled filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said formed lamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising an inclined furnace provided with atubular heating chamber, heating means surrounding said tubular chamberfor supplying heat thereto, means connected to said tubular chamber forcausing rotation thereof to enable said coiled filamentary sections tobe uniformly heated as they gravitate through said heating chamber toanneal and definitely set said sections, means for passing a gaseousatmosphere of Wet hydrogen through said tubular chamber and into contactwith all portions of each individual section to thoroughly clean thesame preparatory to their incorporation in incandescent electric lamps,and vibratory means connected to said tubular heating chamber forcausing aslight vibration thereof to assist gravitation of .eachindividual section through said furnace.

6. An apparatus for forming and treating illaments for incandescentelectric lamps comprising means for Winding coiled filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said formed lamentary sections from said last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising a` furnace, means for gravitating saidcoiled lamentary sections through said furnace immediately followingtheir formation, means for heating said sections during their passagethrough said furnace to definitely set said sections, means for passinga gaseous atmosphere through said furnace and into contact with allportions of each coiled lamentary section to thoroughly clean the same,and means connected to said furnace and operable to assist the movementof said sections through 'said furnace.

7. An apparatus for forming and treating filaments for incandescentelectric lamps comprisl ing means for winding coiled 'filaments intosections of predetermined length in the absence of a mandrel, means fordischarging said for. ied lamentary sections fromsaid last mentionedmeans, means connected to said discharge means for annealing andcleaning said sections comprising a furnace provided with a tubularheating chamber, means for rotating said tubular chamber to uniformlyheat all portions of said coiled lamentary sections as they gravitatethrough said heating chamber immediately following their initialformation, means surrounding said heating chamber for heating saidcoiled sectons to definitely set said sections, means for passing agaseous atmosphere through said heating chamber and into contact withall portions of each coiled section to thoroughly clean the samepreparatory to their incorporation in incandescent electric lamps,.andmeans connected to said FREDERIC E. SU'ITER.

